EVALUATION OF THE PRESENT THEORETICAL BASIS FOR DETERMINATION OF PLANETARY SURFACE PROPERTIES BY EARTH-BASED RADAR

摘要

Spaceflight programs such as the planned Viking landing on Mars often require the determination of planetary surface slopes and surface dielectric constants by Earth-based methods. Heavy reliance is often placed on radar backscattering data for estimation of these surface properties. The present report, which is primarily directed toward users of such estimates rather than toward radar workers, is an assessment of the basic theory by which the raw radar data are interpreted. It is shown that serious difficulties and internal inconsistencies are present in the available theoretical formulas. The discussion brings into serious question the reliability of the presently available results for these surface properties as obtained by Earth-based radar methods, and it points out that the theoretical difficulties are not likely to be remedied in the near future.